Maar volcano: A volcanic crater without a cone, believed to have been formed by an explosive eruption of trapped gases.

Mafic mineral: A dark-colored mineral rich in iron and magnesium, especially a pyroxene, amphibole, or olivine.

Magma: Molten rock material that forms igneous rocks upon cooling. Magma that reaches the surface is referred to as lava.

Magmatic water: Water that is dissolved in a magma or that is derived from such water.

Magnetic stratigraphy: The study and correlation of polarity epochs and events in the history of the Earth's magnetic field as contained in magnetic rocks.

Magnetometer: An instrument for measuring either one orthogonal component or the entire intensity of the Earth's magnetic field at various points.

Magnitude: A measure of earthquake size, determined by taking the common logarithm base 10) of the largest ground motion observed during the arrival of a P-wave or seismic surface wave and applying a standard correction for distance to the epicenter.

Mantle: The main bulk of the Earth, between the crust and core, ranging from depths of about 40 to 3480 kilometers. It is composed of dense mafic silicates and divided into concentric layers by phase changes that are caused by the increase in pressure with depth.

Massive rock: A rock that is little or not at all broken by joints, cracks, foliation, or bedding, tending to present a homogeneous appearance.

Mass movement: A downhill movement of soil or fractured rock under the force of gravity.

Mass spectrometer: An instrument for separating ions of different mass but equal charge (mainly isotopes in geology) and measuring their relative quantities.

Maturity: A stage in the geomorphic cycle in which maximum relief and well-developed drainage are both present.

Meander: Broad, semicircular curves in a stream that develop as the stream erodes the outer bank of a curve and deposits sediment against the inner bank.

Mechanical weathering: The set of all physical processes by which an outcrop is broken up into small particles.

Medical geology: The application of geologic science to problems of health, especially those relating to mineral sources of toxic or nutritious elements and natural dispersal of toxic pollutants.

Mesosphere: The lower mantle.

Metamorphism: The changes of mineralogy and texture imposed on a rock by pressure and temperature in the Earth's interior. Meteoric water: Rainwater, snow, hail, and sleet.

Meteorite: A stony or metallic object from inter-planetary space that penetrates the atmosphere to impact on the surface.

Micrometeorite: A meteorite less than 1 millimeter in diameter.

Microseism: A weak vibration of the ground that can be detected by seismographs and which is caused by waves, wind, or human activity, but not by an earthquake.

Migmatite: A rock with both igneous and metamorphic characteristics that shows large crystals and laminar flow structures. Probably formed metamorphically in the presence of water and without melting.

Mineral: A naturally occurring element or compound with a precise chemical formula and a regular internal lattice structure. Organic products are usually not included.

Mineralogy: The study of mineral composition, structure, appearance, stability, occurrence, and associations.

Miogeosyncline: A Geosyncline that is situated near a craton and receives chemical and well-sorted elastic sediments from the continent.

Mohorovic discontinuity: The boundary between crust and mantle, marked by a rapid increase in seismic wave velocity to more than 8 kilometers per second. Depth: 5 to 45 kilometers. Abbreviated "Moho" or "M-discontinuity."

Monocline: The S-shaped fold connecting two horizontal parts of the same stratum at different elevations. Its central limb is usually not overturned.

Moraine: A glacial deposit of till left at the margin of an ice sheet. See specifically by name, ground moraine, longitudinal moraine, medial moraine, and terminal moraine.

Mountain: A steep-sided topographic elevation larger than a hill; also a single prominence forming part of a ridge or mountain range.

Mudflow: A mass movement of material finer than sand, lubricated with large amounts of water. Mudstone: The citified equivalent of mud, a fine grained sedimentary rock similar to shale but more massive.

Mylonite: A very fine lithified fault breccia commonly found in major thrust faults and produced by shearing and rolling during fault movement.

MACHINE: is any device that uses energy to perform some activity.A simple machine is a device that transforms the direction or magnitude of a force without consuming any energy

MAGNITUDE: a number characteristic of a quantity and forming a basis for comparison with similar quantities, as length.

Materials are substance or components with certain physical properties which are used as inputs to production or manufacturing

Mechanical Engineering: is an engineering discipline that involves the application of principes of physics for analysis,design, manufacturing , and maintenance of mechanical systems . Mechanical engineering is one of the oldest and broadest engineering disciplines.

Mineral: is A solid homogeneous crystalline chemical element or compound that results from the inorganic processes of nature.

Mining and geological engineers, including mining safety engineers find, extract, and prepare coal, metals, and minerals for use by manufacturing industries and utilities. They design open-pit and underground mines, supervise the construction of mine shafts and tunnels in underground operations, and devise methods for transporting minerals to processing plants.

Native metal: A natural deposit of a metallic element in pure metallic form, neither oxidized nor combined with sulfur or other elements.

Neap tide: A tide cycle of unusually small amplitude, which occurs twice monthly when the lunar and solar tides are opposed-that is, when the gravitational pull of the Sun is at right angles to that of the Moon.

Nebula: An immense, diffuse body of interstellar gas and dust that has not condensed into a star.

Nebular hypothesis: A theory of the formation of the planets that states that a rotating nebula contracted and was then torn into fragments by centrifugal forces, with planets condensing from the fragments.

Neutron: An electrically neutral elementary particle in the atomic nucleus having the mass of one proton.

NOUN:The part of speech that is used to name a person, place, thing, quality, or action and can function as the subject or object of a verb, the object of a preposition, or an appositive

NUMBER:a word or symbol, or a combination of words or symbols, used in counting or in noting a total.